Golf tee with enhanced aerodynamic drag

ABSTRACT

This invention is a golf tee having an aerodynamic drag portion with a relatively large frontal area and aerodynamic drag coefficient, an intentionally minimized mass, and a subsequent reduction in flight distance upon being struck with a golf club. This reduced flight distance coupled with the relatively large area of the drag portion makes this tee relatively easy to find. It is economically feasible, therefore, to make this tee from a virtually indestructible but relatively more expensive material such as polyurethane. The resulting tee has significantly greater operational life than conventional tees.

BACKGROUND

1. Field of Invention

This invention is a golf tee assembly containing a tee portion whichelevates a golf ball and an aerodynamic drag portion to reduce itsflight distance after being struck by a golf club. This reduced flightdistance along with the relatively large size of the aerodynamic dragportion provides a tee which is relatively easy to find. In a preferredembodiment, the two portions are two distinct members which areadjustably attached. Since the tee is easily found, it is practical tomake the tee from a durable but relatively more expensive material, suchas polyurethane, providing a tee with an exceptionally long operationallife.

2. Description of Prior Art

Common rules of the game of golf allow the use of a tee to elevate agolf ball above the ground on the first stroke of a hole. This makesstriking the ball easier, especially with golf clubs with relativelylarge heads such as a driver or fairway wood. Tees commonly used todayare made from wood or plastic, have a pointed end for insertion into theground and a recessed top to support a golf ball. When the ball isstruck with the club, the tee is usually also struck and an initialvelocity is imparted to the tee. This velocity, for any particular clubimpact, is essentially independent of the tee's mass since the tee'smass is considerably smaller than the mass of the club head. An initialkinetic energy is therefore imparted to the tee, the magnitude of thiskinetic energy being essentially proportional to the tee's mass. For agiven club impact, a conventional tee can travel a relatively largedistance in various directions making it difficult to find. Breakage isalso common, especially in the case of wooden tees. Conventional teestherefore have a relatively short life due to loss or breakage.

One way to prevent tee loss is to simply tie the tee to the ground. TwoU.S. patents, U.S. Pat. No. 6,494,796 to Echaves (2002) and U.S. Pat.No. 5,413,348 to Basso (1995) show two methods of tying a tee to theground. Present United States Golf Association rules prevent using a teewhich can be used to indicate an intended line of play. The tethersshown in these two patents probably violate this rule since the tethercould be positioned to indicate an intended line of play.

Several patents for golf tees show the use of a disk-shaped member intheir construction but which are not optimally effective in reducing thedistance the tee can travel after being struck by a golf club. U.S. Pat.No. 6,475,107 to Sand (2002) shows a tee assembly containing adisk-shaped member, but the purpose of the disk-shaped member is toprovide consistent elevation of a golf ball above a teeing surface. Thediameter of the disk is shown as having a diameter significantly smallerthan the diameter of a golf ball which means it would have limitedaerodynamic drag. Also, the two members of the tee assembly as shown arerelatively easily separated, and if separated, the disk-shaped memberwould not reduce the flight distance of the ball-supporting member.

U.S. Pat. No. 5,052,689 to Lettrich (1991) shows another disk-shapedmember used to provide consistent ball elevation. Here again, the diskis typically shown as having a diameter considerably smaller than a golfball, limiting its aerodynamic drag. In addition, the disk and its shankare shown as having a relatively large thickness, thereby resulting in adisk and shank with a relatively large mass. This large mass, combinedwith the initial velocity imparted to the tee by the club, means the teeassembly will have a relatively large amount of initial kinetic energyand its travel distance will be relatively great.

U.S. Pat. No. 5,242,161 to Wilkirson (1993) also shows a tee assemblywhich contains a member having a disk-shaped portion but with a diametergreater than the diameter of a golf ball, but here again this member asshown can easily separate from the ball-supporting member. Also, themember containing the disk-shaped portion is drawn as being relativelylarge in size, with relatively thick members, and therefore would have arelatively large mass and relatively large travel distance.

U.S. Pat. No. 4,998,732 to Gallant (1991) shows a tee assemblycontaining a disk-shaped member attached to a ball-supporting member.The diameter of the disk portion is shown as being appreciably smallerthan a golf ball, and the disk portion is shown as being relativelythick which means relatively large mass, and the travel distance of thetee will be relatively large. In addition, one side of the disk portionis shown as having a tapered shape which would have a relatively lowaerodynamic drag coefficient (it would be considered to have a goodaerodynamic design), and this shape would further reduce the aerodynamicdrag. Therefore, this assembly is also not optimally designed to provideenhanced aerodynamic drag with reduced mass.

OBJECTS AND ADVANTAGES

An object of this invention is a golf tee assembly having an aerodynamicdrag portion with an aerodynamic drag surface which reduces the distancethe tee travels when struck by a golf club.

A further object of this invention is a golf tee assembly having anaerodynamic drag surface with a shape which increases the aerodynamicdrag coefficient of the surface.

A further object of this invention is a golf tee assembly which isrelatively easy to find because of its reduced travel distance and arelatively large area of its aerodynamic drag surface.

A further object of this invention is a golf tee assembly which is madefrom an operationally indestructible material, which along with itsbeing relatively easy to find, results in a tee assembly which can beused many times before breakage or loss.

A further object of this invention is a tee assembly which complies withcommonly accepted rules of golf.

Still further objects and advantages will become apparent from aconsideration of the ensuing description and drawings.

DRAWING FIGURES

FIG. 1 shows a disassembled view of the golf tee of this invention and

FIG. 2 shows in cross-section the tee of this invention placed in theground with a ball in position to be struck by a golf club.

REFERENCE NUMERALS IN DRAWINGS

-   5 golf tee assembly-   10 tee portion-   20 tee tip-   30 recessed top-   40 shoulder-   50 shaft-   60 aerodynamic drag portion-   70 drag portion hole-   80 golf ball-   90 ground

DESCRIPTION AND OPERATION-FIGS. 1 & 2

FIG. 1 shows a golf tee assembly 5 of this invention which contains atee portion 10 for elevating a golf ball and an aerodynamic drag portion60. Tee portion 10 contains a tip 20 for insertion of assembly 5 in theground, a recessed top 30 for holding a golf ball, a shoulder 40, and ashaft 50 having a diameter smaller than the diameter of shoulder 40 andtop 30. Aerodynamic drag portion 60 contains a hole 70, the diameter ofhole 70 being preferably slightly less than the diameter of shaft 50 butcertainly smaller than the diameter of shoulder 40 and top 30. Apreferred shape for the perimeter of drag portion 60 is a circle, makingportion 60 a circular disk, thereby preventing portion 60 and thereforeassembly 5 from indicating any preferred direction, therefore complyingwith common rules of golf. Drag portion 60 is normally made of arelatively resilient material, such as polyurethane, so that hole 70 canbe stretched over shoulder 40, therefore positioning and captivatingdrag portion 60 on shaft 50 between shoulder 40 and top 30. Tip 20,shoulder 40, and shaft 50 form a barb, and with hole 70, portion 10 andaerodynamic drag portion 60 cannot separate.

FIG. 2 also shows tee assembly 5 with similar parts as described abovebut shown in position with tip 20 inserted in ground 90. A golf ball 80is sitting on recessed top 30 ready to be struck by a golf club (notshown). When using tee assembly 5, the golfer inserts tip 20 into ground90 to any desired distance to provide a preferred location of ball 80relative to ground 90. Drag portion 60 is then preferably slid alongshaft 50 positioning drag portion 60 against ground 90. Also, dragportion 60 is shown as optimally having a contoured thickness. Thelarger thickness near hole 70 and at the perimeter of drag portion 60provides the strength requirements of portion 60, but the reducedthickness in the remaining sections provide an optimally reduced mass.The shape shown also has an enhanced aerodynamic drag coefficient, aterm which indicates how “streamlined” an object is. The shape shown hasa relatively high aerodynamic drag coefficient, having a shape somewhatlike a parachute.

Tee assembly 5 has a reduced chance of being lost because aerodynamicdrag portion 60 provides tee assembly 5 with a relatively largeaerodynamic drag relative to its mass. The resulting reduced flightdistance, along with the relatively large surface area of drag portion60, makes finding assembly 5 easier than a tee without portion 60.Conventional tees, which have a shape similar to tee portion 10 exceptthey do not have shoulder 40, have relatively good aerodynamiccharacteristics, looking somewhat like a bullet. Therefore, when struckby a golf club, they can fly a considerable distance, and this, combinedwith their relatively small size, sometimes makes them hard to find.

The term aerodynamic drag denotes a force exerted on an object as ittravels through a medium such as air. The integral of this force overdistance traveled is the kinetic energy lost by the object in travelingthe distance. The aerodynamic drag of a body is affected by its area andits aerodynamic drag coefficient. A flat circular disk has anaerodynamic drag coefficient of about 1.3; if contoured as shown in FIG.2, it will increase to 1.5 to 2.0. A bullet by comparison has anaerodynamic drag coefficient of only about 0.3. Therefore, to minimizetravel distance, an object should have a relatively large area with arelatively high drag coefficient, and its mass should be low giving it alow kinetic energy for any given initial velocity. An indicator whichrepresents the effectiveness of tee assembly 5 of this patent inlimiting travel distance, called a drag indicator, is the product of themaximum frontal area it can present to the approaching air times thedrag coefficient of this area divided by the mass. A tee assembly 5 wasconstructed from polyurethane, tee portion 10 having a total length ofabout 64 mm (2.5″), drag portion 60 had a diameter of about 42 mm(1.66″) (approximately the diameter of a golf ball), and assembly 5 hada total mass of 4.4 grams. The maximum area of disk 60 is therefore 1385mmˆ2, and using a drag coefficient of 1.5 for the surface shape shown,the drag indicator for the tee of this invention is 1385 mmˆ2*1.5/4.4g=472 mmˆ2/gram. By comparison, a conventional wooden tee has a mass of1.1 grams with a top diameter of 11 mm (0.43″) for an area of 95 mmˆ2,and when flying “like a bullet” with an estimated drag coefficient of0.3 gives a drag indicator of only 95 mmˆ2*0.3/1.1 g=26 mmˆ2/gram.

Inventor has used conventional tees, and typically these tees are eitherlost or broken 30% to 50% of the time. In other words, if ten driveswere made with these tees, approximately 3 to 5 tees would be lost orbroken. A tee was constructed from polyurethane having a design similarto assembly 5, and Inventor has made over 1000 drives with this tee and“it's still going”. A typical flight distance is less than 3 meters, andthis small distance, coupled with the relatively large surface area ofdrag portion 60, enables the tee to be found relatively easily.

Since drag portion 60 in the preferred embodiment has a circularperimeter (it is a round disk), it cannot be used to indicate apreferred line of play and therefore complies with commonly used golfrules.

SUMMARY, RAMIFICATION, AND SCOPE

Accordingly, this invention is a golf tee assembly which has aerodynamicflight characteristics somewhat like a badminton birdie. It has anaerodynamic drag portion which provides the assembly with a relativelylarge aerodynamic drag compared to its mass. This large aerodynamic dragreduces the tee's flight distance when struck with a golf club, and thisreduced flight distance, coupled with the relatively large area of thedrag portion, makes it easily found. It is economically justifiedtherefore to make this tee from a relatively more expensive butoperationally unbreakable material, such as polyurethane, which coupledwith its reduced likelihood of loss, provides a tee which rarely needsreplaced.

Although the description above contains many specificities, these shouldnot be construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. For instance, drag portion 60 can be some other shapethan round and it will still reduce flight distance. Portion 60 maycontain additional holes or be made from a screen-like material tofurther reduce its mass. The shape of tee portion 10 can be changed aslong as drag portion 60 cannot operationally separate from tee portion10. Thus, the scope of the invention should be determined by theappended claims and their legal equivalents, rather than by the examplesgiven.

1. A golf tee containing a first portion which supports a golf ball anda second portion which provides an aerodynamic drag, attachment meanswhereby said second portion can affect a movement of said first portionwhen said tee is traveling through the atmosphere, said second portioncontaining a surface upon which said atmosphere applies an aerodynamicdrag force when said surface travels through said atmosphere, saidsurface having a perimeter which encloses a frontal area measured inmillimeters squared, said surface having an aerodynamic dragcoefficient, said tee having a mass measured in grams, a drag indicatorwhich is said area measured in millimeters squared times saidaerodynamic drag coefficient divided by said mass measured in grams, andwherein said drag indicator is greater than three hundred millimeterssquared per gram.
 2. The tee of claim
 1. wherein said perimeter is acircle.
 3. The tee of claim
 2. wherein the diameter of said circle isapproximately the diameter of a golf ball.
 4. The tee of claim 1.wherein said first portion is made from a resilient material.
 5. The teeof claim
 4. wherein said resilient material is polyurethane.
 6. The teeof claim
 1. wherein said second portion is made from a resilientmaterial.
 7. The tee of claim
 6. wherein said resilient material ispolyurethane.
 8. The tee of claim
 1. wherein said surface having aperimeter which encloses a frontal area has an aerodynamic dragcoefficient which is greater than the aerodynamic drag coefficient of aflat surface having the same perimeter which encloses the same frontalarea.
 9. The tee of claim
 1. wherein said second portion has a shapesimilar to a disk with a diameter greater than 20 times its averagethickness.
 10. The tee of claim
 1. wherein said first portion is madefrom an operationally indestructible material.
 11. The tee of claim 10.wherein said material is polyurethane.
 12. The tee of claim
 1. whereinsaid second portion is made from an operationally indestructiblematerial.
 13. The tee of claim
 12. wherein said material ispolyurethane.
 14. The tee of claim
 1. wherein said attachment means is abarb on said first portion and a hole in said second portion.